The failure of the congressional supercommittee to reach a deal on the budget is a sad reflection of the polarisation in the US today. But this failure has roots that go well beyond the individuals charged with coming up with a plan to reduce the deficit; they go to the very nature of the political system. And while this committee has failed ignominiously, it contains the seed of an idea that might show us a way out of paralysis.

Americans take great pride in a constitution that limits executive power through a series of checks and balances. But those checks have metastasised. And now America is a vetocracy. When this system is combined with ideologised parties, one of which sees even the closing of tax loopholes as an unacceptable tax increase, the result is paralysis.

The problems of the US system are all too apparent when compared with the classic British Westminster system: parliamentary, with first-past-the-post voting, no federalism or decentralisation, and no written constitution or judicial review. Under such a system, governments are typically backed by a strong legislative majority. The present government’s coalition is highly unusual for the UK, which typically gives the leading party a strong parliamentary majority. A simple majority plus one in the House of Commons can make or overturn any law in the land, which is why it has sometimes been referred to as a democratic dictatorship.